


Systematic Desensitization: or How Leonard McCoy Learned to Love His Ass

by pippen2112



Category: Star Trek: Alternate Original Series (Movies)
Genre: Anal Sex, Bondage, Explicit Language, Explicit Sexual Content, Fingerfucking, M/M, Oral Sex, Sub!Bones, Top!Kirk, Topping from the Bottom, bottom!Bones
Language: English
Status: Completed
Published: 2013-09-20
Updated: 2013-09-20
Packaged: 2017-12-27 00:04:29
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,954
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/971875
Author URL: https://archiveofourown.org/users/pippen2112/pseuds/pippen2112
Summary: <blockquote class="userstuff">
              <p>A prequel to "Surprise, Surprise".</p><p>Leonard “Bones” McCoy wasn’t born a natural bottom.  In fact, he’s had anything more than an objective appreciation for his ass.  Luckily, Jim Kirk never met an obstacle he couldn’t overcome.</p><p>Now complete.</p>
            </blockquote>





	Systematic Desensitization: or How Leonard McCoy Learned to Love His Ass

**Author's Note:**

> For STID Kink Meme Prompt: http://strek-id-kink.livejournal.com/2836.html?thread=1456660#t1456660
> 
> So I have this very specific kink that basically has a somewhat aloof/cranky/arghgrr!manly/stoic man discovering just how damn much he enjoys being fucked in da butt.
> 
> So basically, any of the following three; Spock, McCoy, Sarek (if you are into pegging, hehe) having that discovery.
> 
> I'd prefer the following pairings; Kirk/Spock, Kirk/Bones, Spock/Bones, Bones/Spock or Amanda/Sarek.
> 
> Bonus points for:  
> \- Rimming  
> \- Prolonged fingering  
> \- Pillow biting.

“Ahhhh, oh fuck me, Bones! Right fucking there! Yes, ooooooh.”

 

“Dammit Jim, keep it down! I swear, you don’t have a subtle bone in your body,” Leonard growls.

 

“Oooh, maybe one, but not as often as I’d like.”

 

Leonard’s hip flinch forward despite himself. “Damn punny infant.”

 

Its times like these that make Leonard McCoy rue the day he plopped down next to Jim in that damn shuttle and the ensuing friendship that formed. Sure, there’ve been perks; being best friends and not-so-occasional fuck buddies with Jim Kirk, a man who’s sex drive is as ridiculous as the rest of him, means there’s never a dull moment. But sometimes--like right now, with his arms tied over his head and Jim screeching like a monkey while pistoning up and down over Leonard’s hard cock--being friends with Jim is like hopping from one huge embarrassment to the next.

 

Of course, Jim chooses that moment to punctuate his sentence by squeezing tight around Leonard's penis, and Leonard’s eyelids flutter closed. If his arms were less preoccupied with being tied down, he’d smack Jim for every one of his inconvenient puns. When opens his eyes, he sees Jim smirking down at him, pleasure-glazed as his hand pumps over his prick in time with his thrusts. That shouldn’t be half as hot as it is, but Leonard can’t look away as the heat pooled in his groin pulses and throbs, begging for release.

 

He glowers and tugs on his bonds to distract himself, but the little lines of pain crisscrossing over his arms and wrists light fire in his blood. With one, two, three more thrusts, he comes in Jim’s ass. Above him, Jim groans. His hand moves faster, his hips stutter, and his ass clenches something fierce around Leonard’s spent cock. He feels Jim’s come splatter across his chest and opens his eyes as Jim slinks off the bed and into the adjoining bathroom Leonard’s earned as a second year, advanced track medical student. Jim returns a few minutes later with a damp washcloth, and he carefully wipes Leonard clean. When he’s done, he lobs the cloth vaguely in the direction of the bathroom and then snuggles into Leonard’s side without bothering to untie his arms.

 

“You know what, Bones? You wear me out in the best way.”

 

Leonard scowls a little and tries to shift into a more comfortable position. He's warm and sated, like he could slip into the longest, most luxurious nap ever. Jim nuzzles into his armpit and tangled their legs together. He tries not to notice Jim’s hair tickling the underside of his arms. Sometimes, Jim is remarkably sweet and endearing. Othertimes, he’s a horny hellion chasing his next orgasm.

 

He sighs and settles into the mattress. Jim’s head perked up. “What’s with the sigh?”

 

“Nothin’ much. Just thinkin’ ‘bout how over-blown you are.”

 

Jim sits up quickly--too quickly for someone who just got his ass worked over--and his brow furrows in confusion. “What’re you talking about, Bones?”

 

Leonard grins at that. He’s always unduly pleased when he can catch Jim off-guard. “Jim, I know you go above and beyond the call of duty with everything you do, but there is no way in hell my dick feels _that_ good. I don’t need my damn ego stroked.”

 

Jim’s eyebrows shoot farther up his forehead, and he hurriedly unties the ropes from Leonard’s wrists and rubs along the creased, tender skin. He holds Leonard’s wrist in his hands. “Come on, Bones. You know all that anatomy shit. The human body’s built to enjoy sex.”

 

Leonard rolls his eyes. “There’s a difference between enjoying something and howling like a damn banshee. The neighbors are gonna start thinking I’m murdering you.”

 

Jim smirks. “I bet you’d get a kick out of it if you tried it. Not murder. Bottoming. I mean, you already get your kicks on being tied up,” Jim said, lightly wrapping his hand around Leonard’s wrists as if to demonstrate his point; a small part of Leonard whimpers and dies at the small display of dominance. Seriously. He needs to get a grip on himself sooner than later, before Jim gets his way and turns him into a quivering mass of fucked-out flesh. “It’ll be like taking it one step farther, and it feels amazing.”

 

Leonard doesn’t doubt it. He’s seen Jim’s cock up close and personal. It’s a touch narrower than his own, but it’s long enough to touch the back of his throat. While choking on his best friend’s dick is never a pleasant experience, it never fails to make Jim come hard and fast. He takes pride in those moments, even if he gets the occasional face-full of cum.

 

Despite the comforting weight of Jim’s grip around his wrist, Leonard pulls away. The whole bondage aspect of his sexuality is a fairly new development. Before Jim waltzed into his life and crawled into his bed, he’d seen himself as your run-of-the-mill male heterosexual whose needs didn’t extend far beyond the palm of his hand. Jim, however, turned things upside down with his damn cheery disposition and his willful determination.

 

He remembers the first time Jim made a pass at him, when they were both drunk off their asses and eager for another warm body. He remembered the heat of Jim’s fingertips pushing his shirt off his shoulders, the bunched sleeves catching on his hands and leaving his arms immobile. He remembered Jim pressing him into the nearest wall, taking both their cocks in hand, and bringing them both to a breathless climax. Hell, just thinking about it gets him going again.

 

Leonard just shakes his head and looks away from Jim to hide his flush. “I don’t think so, Jim. Having things shoved up my ass ain’t my cup of tea.”

 

“But--”

 

“Dammit Jim, just leave it.”

 

And surprisingly, Jim does. He just settles back down, cuddles close to Leonard, and doesn’t say another damn word.

 

Looking back on it, Leonard really should have recognized this as a very, _very_ bad sign.

 

\--

 

A week later, Leonard stumbles into his dorm, body sore and bleary eyed from exhaustion. He’d known today was going to be a bad day; he’d felt it deep in his bones before he’d even woken up, but he’d ignored his gut instinct to call in sick and go back to bed. His mistake, really. Now, he’s home and he has what feels like a million and one things to do before class tomorrow, but all he wants is to collapse.

 

He’s stuck standing halfway between the desk and the bed, trying to decide, when the door slides open and Jim waltzes in, carrying a bag of what smells like the greasiest, most deliciously artery-clogging Mexican food he’s ever smelled. His stomach grumbles insistently, and Leonard turns and heads to the sofa. He plops beside Jim with a groan.

 

“Long day?”

 

“You don’t know the half of it.”

 

Jim smirks, sets the food down on the coffee table, but doesn’t get about to unpacking. He turns toward Leonard with concern wrinkling his brow. The fact that Leonard hadn’t gone off on one of his rants must be a dead giveaway of how much he doesn’t want to talk about today. Jim just looks at him for a few minutes before a soft smile touches his face, and he leans forward and presses a light kiss to Leonard’s mouth. Leonard sighs, tilts his head back slightly, and settles as some of the tension rolls off him.

 

Seeing Leonard visibly relaxing, Jim redoubles his efforts, slipping a hand to cup Leonard’s neck and sliding effortlessly into his lap. He keeps his kisses gentle for a few minutes until Leonard’s hands settle on his hips. Jim groans and presses his clothed cock against Leonard. As Jim moves down to start mouthing and nipping at his neck, Leonard closes his eyes and relishes the feeling. No matter how the sex goes--and it has gone wildly, spectacularly wrong on occasion (it’s Jim Kirk after all)--this is always his favorite part: the moment right after it stops being just kissing and right before it turns overtly sexual. It’s one of the best things about Jim; his best-friend-turned-lover has always had a really good sense of when to pull the emergency brakes on the fuck train before they barrel into a less than ideal situation. He doesn’t know if that’s because Jim has a strong understanding of people in general, or if he just knows Leonard that well. Right down, with Jim nibbling at his collarbone and sliding his hands up under his shirt, he doesn’t care which.

 

Jim mouths up to his ear and asks, “Do you want more, Leonard?”

 

The words send chills through him. His half-hard cock takes full interest in the proceedings, straining against the fly of his scrubs. Yes, Jim knows how to navigate the boundary between comfort and foreplay with ease. He also know how to barrel right past it and leave him a quivering mess of a human being. Clearly, today it’s gonna be the latter, and no matter how tired he is, he knows Jim will make it worth his while.

 

“Yes, sir,” he hisses as Jim runs his teeth over his earlobe.

 

Jim presses his hips flush with Leonard’s, his cock hard and hot through the denim of his civvies. His hips grind forward reflexively. Jim chuckles and cants his hips back and away. “Hands up.”

 

Leonard’s hands fly up immediately, and Jim yanks up his scrub top, deftly looping it around his hands. It’s not so tight that he can’t get out of it, but it’s not loose enough to fall off. Leonard swallows and drops his hands behind his head, waiting for his next instruction.

 

Jim takes his time kissing and licking down the length of Leonard’s chest. He takes several minutes to lavish his nipples and to bite at his belly button. Leonard very nearly whimpers a time or two, but he bites his lower lip and looks away. Technically, it’s not breaking any rules until Jim orders him not to look away.

 

Jim slides off him and between his spread knees. Fuck, he had not been expecting this, but he’s a red-blooded male; ain’t no way he’s turning down a blowjob if Jim’s got his heart set on it.

 

“Hips up.”

 

He swallows and lifts his hips. Jim eases down his scrubs and underwear until they’re stuck around his calves and drags his hips to the edge of the sofa before pushing him back down. Leonard tries not to moan at the man-handling. It’s just another development he hasn’t quite come to grips with, and as such, he’s not ready to give Jim one more weapon in his sex-arsenal.

 

His thoughts grind to a halt when Jim sucks his dick into his mouth with almost no preamble. Most of the time, Jim’ll tease him with kitten licks and kisses until he’s borderline begging for him to “put my fuckin’ cock in your fuckin’ mouth, Jim!” The changeup has him gasping.

 

And Jim doesn’t stop. Not to catch his breath. Not to open his own pants and jerk off. Not until Leonard’s a pile of human glue seconds away from begging for more, tiptoeing along the edge. He logically knows he’s probably making some kind of sound, but he’s not consciously aware of it. All he knows right now is wet heat, and suction, and so fuckin’ close.

 

He barely notices the slick press below his balls, not until he feels suddenly full. His hips buck at that, and he thanks every god he knows that Jim doesn’t have a gag reflex. His ass clenches. Pain shoots through him, followed almost immediately by a rolling, intense wave of please that has almost nothing to do with Jim’s mouth on him, but it kicks him over the edge. He shoots into Jim’s mouth and’s left gasping.

 

After that, he collapses onto his sofa, mostly naked and thoroughly sated. He can hear Jim fisting his cock between his knees. Normally, he’d slide down and give him a hand with that, but the exhaustion’s set back in with a vengeance. Distantly, he hears Jim groan with his orgasm, but he’s already most of the way unconscious.

 

It’s not until the next morning, well after Jim’s half-carried him to bed and snuggled in behind him, when Leonard goes to use the head and notices a residual slickness between his ass cheeks. When he goes investigating, his fingers come back slick. His eyes go wide.

 

The flurry of cursing Jim wakes up to is truly legendary.

 

\--

 

Later, much later, after Leonard's fury has abated and Jim's initiated I'm-sorry-I-didn't-ask-before-sticking-a-finger-up-you-butt-but-in-my-defense-you-really-liked-it sex, Leonard conveniently forgets the incident. Perhaps he thinks that Jim is satisfied by this little venture.

 

He is sorely mistaken.

 

The next time Jim ties Leonard's arms behind his back and starts to tease him with playful licks and hot breathes, Jim stops partway through and looks up at Leonard with a sly grin.

 

"I wanna try something," he says plainly, "and I think you'll enjoy it."

 

Leonard tries to shake some of the arousal from his mind, but doing so jostles his arms and pulls at his bindings. Another wave of arousal crashes over him. Then, Jim starts trailing his fingertips over his stomach and thighs, dangerously close to his cock but still maddeningly far away. He swallows. The odds of this going sideways are astronomically high, but at the same time, he trusts Jim to know his limits, to push him just far enough without tossing him over the edge. So, he nods and his stomach drops when Jim's face pulls into a smile.

 

"That's my boy," Jim says, turning Leonard onto his stomach with firm hands. "Prop yourself up on your knees."

 

The movement strains his back until Jim shoves two pillows under his hips and rubs a soothing hand on the curve of his spine. He gets goose bumps on his ass, the air kissing his flushed skin. His breath speeds up, aware of how exposed he his. Jim presses kisses along his spine and runs his hands over his back with a firm presence.

 

"I've got you, Leonard," Jim whispers into the nape of his neck. "Just say the word and I'll get you out of this. Only gonna make you feel good."

 

With a shudder, Leonard nods. "Yes, sir." He turns his head to the side and closes his eyes.

 

For a few minutes more, Jim stays pressed up against his back, mouthing at and touching his skin until his breath hitched from arousal not apprehension and his hips rocked backward of their own accord. Leonard felt Jim cup his ass, raking his nails across the flesh and slowly sliding back between his spread legs. Jim kissed every inch of his skin and withdrew with a small smack. If Leonard gasped and moaned, he'd deny it til the grave.

 

With slow, steady pressure, Leonard felt Jim slowly pull his cheeks apart. He stilled, face flushed from the embarrassment. Jim could see…well…everything. It took all his focus not to kick back and run. There was a rush of warm air followed by a stream of cool. Jim's thumbs worked in slow circles pressing nearer and nearer. His throat works around the urge to safe word out. It's too much. He can't…

 

And then Jim licks a broad swath up his….and Leonard's hips jerk backward into the warm wet pressure against his hole because holy fuck, what has Jim turned him into?

 

He gets lost in the rim job, breath hitching and moans falling out of his mouth like a porn star. Jim's slight stubble scrapes against his cheeks. He feels Jim's smirk as he dives in with renewed enthusiasm. When Jim pulls back and blows another cool breath over his dampened skin, he whimpers and cursed. "Fuck, what…what've…what've you done to me?"

 

"Told ya you'd like this," Jim replies, drawing back slightly.

 

Before Leonard can protest the sudden absence of tongue, he feels a firmer pressure against his asshole, then the slick fire and Jim's fingers are back inside him, as full as before, but given the thorough rimming he's received, the pleasure feels sharper and more insistent. He keens and rocks back onto Jim's hand.

 

"Good boy," Jim says, voice low and filled with awe. "Work yourself back onto my fingers. Take what you need."

 

He clenches his jaw and pushes himself backward into quick stuttering thrusts. Eyes squeezed closed, he chases the firm pleasure that dances through his guts. Groans catch in his throat as Jim presses another finger inside, holding Leonard open with his other hand. Watching him. "Fuck," he cries at the realization, feeling his balls start to draw up.

 

All too quickly, Jim pulls back until only his fingertips touch Leonard's hole and he grabs Leonard's balls in a firm grip, effectively ending his orgasm. Leonard tries to regain his momentum, but he's left winded.

 

"Not yet," Jim says firmly. "Slower."

 

"Please," he whispers, working his hips and clenching around air.

 

"No, Leonard. Stay still."

 

And, for the love of whatever's left in his world that's holy, he whines and presses his face into the sheets. He breathes deeply through his nose until his arousal's bedded back down and he's not humping back into James hand. Well, barely. Satisfied with his control, Jim releases his grip and soothe his hand over Leonard's thighs and ass. Leonard can only describe the gesture as possessive and it nearly set him off.

 

"Remember, Leonard. If you start moving, I stop."

 

He nods. "Yes, sir." His words come out breathy and ragged. He wants to drop his hips to the bed and grind out an orgasm, but he doesn't. He stays still. He'll be good.

 

Jim pistons his arm at an almost painful rate, moving so carefully that Leonard can feel every bump and press of Jim's fingers against his insides. Somehow, it riles him up but is nowhere near the unyielding pressure he wants. He balls his fists and digs his nails in to keep himself steady, but it takes his all to keep from squirming. When Jim slowly scissors his fingers, Leonard bite the mattress to keep from groaning. As Jim slides a third finger in, purposefully pressing against his prostate, he nearly collapses.

 

"Fuck, I wish I had a capture for this," Jim says blissfully. "Seriously, you wouldn't believe it given all your protests, but you're just taking it."

 

Shivering, Leonard moaned into the mattress. No, Jim could _not_ talk dirty at a time like this. He didn't have the self-control to hold up against such an onslaught.

 

"You're so good for me, Leonard. Doing what I say even though I know you just wanna fuck yourself back onto me. You'd take everything I'd give you. I wonder if you could take my fist."

 

Leonard's hips stutter. The thought sends another flurry of arousal through him. It terrifies him to think he might want that, but right now, Jim could ask him to can-can dance naked in high heels with a plug up his ass and he'd do it. He'd do anything to keep the buzz going.

 

"No, not today, Leonard. Not any time soon. But some day, I'm gonna work you so open you're gagging for it. Gonna press all the way into you. Gonna fuck you as hard as you deserve, and I'm gonna relish in the tight squeeze of your ass."

 

"Fuck me."

 

The plea pries its way out of his throat, high and needy like he couldn't imagine. If he had enough self-awareness, he'd step back from himself and gape at the pile of human goo Jim has transformed him into. Instead, he's focusing all of his attention on being as still and as good as possible. He can be good, he can listen.

 

Suddenly, he feels Jim pressed along his back, fingers still pumping slowly into his ass. Jim's other hand slips around his front, coiling around his cock in a too dry squeeze that makes his eyes roll back into his head. Jim bites his neck and nuzzles behind his hair as his hands start working in a torturous counterpoint that Leonard is helpless against.

 

"No," Jim whispers into his ear.

 

Maybe it’s the newness of being filled, or the raw pressure of Jim's callouses against his hole. Or the sudden grip around his dick. Or the smell of Jim pressing so close, waiting for him to ask for it and jerking away the prospect at the last second. Hell, maybe it's a genetic strain of McCoy masochism rearing its uncooperative and extremely ill-timed head. Whatever the case, at that moment a sound escapes Leonard, something he's never heard from anyone possessing a pair of testicles, high and needy and so stupidly submissive. In that moment, every muscle in his body clenches. All it takes is two move pumps, one into his ass, one around his cock, and he's fall, shrieking, flailing into the darkness.

 

When he wakes, he's on his back, his bonds untied, and Jim's wiping a warm, wet cloth over his skin, rinsing away both sweat and semen. Jim hums a catchy tune he can't place, something up-tempo and vaguely jingle-esque. Jim smiles at him before swiping the cloth over his legs. "Welcome back, Bones." His grin can only be described as shit-eating.

 

Leonard groans and rolls his neck. "How long was I out?"

 

"A few minutes. Enough for you to catch your breath." Gingerly, Jim lifts his leg and dabs away stray streaks of lube. "Gotta say I'm flattered. I've never made a guy pass out before."

 

"Yeah, yeah," Leonard says gruffly. He finally realizes that Jim's still fully clothed and that while his erection is starting to abate, it's still very much present. His brow furrows. "You didn't fuck me?"

 

Jim smiles and shakes his head. "You were too out of it, caught up in the scene. I didn't." Jim blushes and ducks his head. "You'd made it very clear you didn't want penetration. I wasn't gonna overstep that in-scene."

 

Leonard is gob-smacked. Not that it's unprecedented, mind you. Even if Jim is a horny spitfire with an overly enthusiastic cock, he's always respected boundaries. He might push here and there, and sometimes he might not ask before diving into some activities, but the hard limits he respects. The thoughtfulness makes something in his chest squeeze. Leonard takes Jim's empty hand and twines their fingers together. "Permission granted," he whispers.

 

Jim's answering smile is fucking luminous.

 

\---

 

"Fuck, Bones, you're tight as a vice. Relax!"

 

"You try relaxing when you've got an eight inch cock exploring places that weren't meant to be explor--Fuck!"

 

Jim laughs and rolls his hips again, grinding against Leonard's prostate. Starbursts play across his vision and his penis throbs in response.

 

"Can't a guy get a reach-around here?"

 

"Let me enjoy this for two seconds, Bones."

 

"More like twenty," Leonard whines, clenching again just to be a dick.

 

Jim's groan makes it well worth the effort. "That's cheating!"

 

"I learned from the best. Oh, fuuuuuuuuuck." Leonard moans as Jim thrusts in retaliation. He drops forward and bites the pillow to keep quiet.

 

Some days, Leonard rues the day he met Jim Kirk. Other days, he thanks whatever lessor sex god brought Jim into his life and vows to live a better, more honest life for Jim's continued presence. But usually those days are the one's Jim's taking him apart with his hands, mouth, and cock, so really, it's unfair to hold Leonard to coital promises. After all, he hasn't been fully desensitized yet.

%MCEPASTEBIN%

**Author's Note:**

> Thanks for reading! Please let me know what y'all think! I have a rough idea of where this is going, but I'm always open to suggestions.


End file.
